Maybe it's still no SID
It's another attempt to force AY chip to more complex synthesis of sound (instead of square waves again and again). AY doesn't like to play interesting instruments, so it was a hard work.
You can find here instruments similar to SID and sometimes similar to filters. Worth to note that all of this works without any additional CPU's activity - only 50hz (unlike Atari ST where people use additional CPU's procedures to their AY/YM work).
Well, and finally I wanted You to have something to dance while New Year Party, hahah.
PS: There is still a new album available: http://yerzmyey.i-demo.pl/